<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <input type="text" name="" id="" value="你好小胖">
    <button>按钮</button>
    <script>
        let inp=document.querySelector('input');
        let btn=document.querySelector('button');
        btn.onclick=function(){
            inp.value='小胖你的妙妙呢';
            this.disabled=true;
        }
    </script>
</body>
</html>